The present invention relates to transmission means, like e.g. belts, and in particular toothed belts used in automatic machines for special applications, such as synchronized transport and transferring of articles with precise positioning.
Known belts for special applications, such as conveying articles, typically include a central support layer, defining the belt body, an upper layer, defining the surface for receiving the articles to be conveyed, and a lower layer. The lower layer features teeth which meshes with the teeth of pulley provided in a line of an automatic machine.
The above mentioned central support layer can be made of e.g. a plurality of strands, parallel to each other, e.g. steel or kevlar, dipped, during molding, in a polymeric material, like e.g. polyurethane.
Otherwise, the central layer can be formed only by elastic polyurethane material.
The upper layer, called coating layer, can be formed by a special material with high friction, in order to facilitate keeping the articles to be conveyed in the correct position, or it can be formed by a fabric having low friction, or other materials suited to the required specific operation needs.
The upper layer of the belt coating layer may be provided with relative fittings, which extend vertical or inclined and are suitably shaped, regularly spaced apart to define successive seats for housing the articles to be conveyed.
The most relevant drawback deriving from the use of such belts is the difficulty encountered during installation directly on the corresponding machine, as well as during removal in case substitution is required.
Actually, in order to carry out these operations, and in particular to mount and remove, from one side, the belts on and from the relative pulleys, suitable working space is needed, which can be obtained only by disassembling protective elements or other parts of the automatic machine. These are complicated operations requiring long downtimes of the machine and specialized technicians.
In order to facilitate mounting and removal operations, there have been proposed toothed belts, which can be closed by a joint set between the two facing ends, directly on the machine.
According to a first type of these belts, the terminal section of the two ends to be joined feature appendixes, facing each other and staggered one with respect to the other.
After having moved close the two ends, the appendixes are welded together to define a joint.
Although this kind of belt can be easily assembled on the machine, the realization of the joint by welding requires an intervention of a highly specialized personnel, use of suitable instruments and performing difficult operations which result in considerable downtimes of the machine
In other types of closable toothed belts, the two edges to be joined are closed by a mechanical joint.
The mechanical joint is obtained by an outer plate or strip, which is placed onto the upper coating layer of the belt in a region corresponding to the ends, to join, after the belt has been closed, and then fastened to the ends, thus joining them. Fastening means are used, which cross suitable holes passing vertically made through the belt in a region corresponding to the adjacent teeth.
A so obtained joint makes the belt more rigid in the region corresponding to the joined edges, consequently the belt is less flexible, because of a rigid body which protrudes from the flat surface of the belt.
Moreover, the presence of the plate or strip occupying a portion of the outer surface of the upper coating layer of the belt, aimed at receiving the articles to be conveyed, can constitute an undesired obstacle, and consequently a limitation to the use of the belt, first of all in case of presence of fittings for defining the receiving seats for the above mentioned articles.
The object of the present invention is to propose a joint for toothed belt aimed at conveying articles, which is able to avoid the above mentioned drawbacks of the prior art.
More precisely, the main object of the present invention is to propose a joint which allows the toothed belt to be closed directly on the corresponding pulleys of the automatic machines by a simple and rapid operation, which considerably reduce the machine downtimes and which do not need disassembling of machine elements and covers.
Another object of the present invention is to propose a joint for toothed belt, which ensures a high reliability for any working condition and which provides the belt with suitable flexibility and strength with respect to any pulling stress.
The above mentioned objects are obtained, in accordance with the contents of the claims, by a joint for toothed belt for conveying articles, said belt including:
an inner central layer defining a belt body;
an upper layer, defining a surface for receiving articles to be conveyed; and
a lower layer featuring teeth;
said joint including:
first connecting means, attached in an irremovable way to said central layer in the area of the terminal section of a belt first edge to be joined;
second connecting means, attached irremovably to the central layer in the area of the terminal section of a belt second edge to be joined;
said first edge and sand second edge being designed to be set close to each other to complete a closed loop formed by said belt, with said first connecting means and second connecting means meshing with each other and reciprocally locked in a removable way by locking means, acting crosswise to said belt in an area of said central layer, so as to join said first edge and second edge.
According to the invention, a toothed belt is claimed, which includes:
an inner central layer defining a belt body;
an upper layer, defining a surface for receiving articles to be conveyed; and
a lower layer featuring teeth;
the said toothed belt being formed in a closed loop by a joint including:
first connecting means, attached in an irremovable way to said central layer in the area of the terminal section of a belt first edge to be joined;
second connecting means, attached irremovably to the central layer in the area of the terminal section of a belt second edge to be joined;
said first edge and sand second edge being designed to be set close to each other to complete a closed loop formed by said belt, with said first connecting means and second connecting means meshing with each other and reciprocally locked in a removable way by locking means, acting crosswise to said belt in an area of said central layer, so as to join said first edge and second edge.